Continuity mistake: When the officer tries to disable the bomb, the read out displays 19 seconds. After he drops it, the display shows 29 seconds.
Continuity mistake: Lex's aide is shot in the back as he makes a run for the door. When he goes down he slides head first almost all the way to the door. A few moments later, just as Flynn shoots out the security camera, in the security monitor image Lex's aide is now in a different position.
Continuity mistake: Clark has to save Lana from a bomb as she is unconscious next to it inside a warehouse. As the bomb explodes and Clark runs through the fire to rescue Lana in the overhead shot she is on her side. In the next she is on her back.
Other mistake: When he takes Lana to the Fortress of Solitude, Clark squeezes a rock and when he opens his hand we see a perfectly cut diamond. Problem here is that in the real world, diamonds don't come out of the earth already cut and shaped. (00:04:20)
Continuity mistake: Clark and Martha show up at the barn. The interior rear view mirror is missing when looking out from inside the car, but it is there when looking in the car from outside.
Character mistake: While Clark and Chloe are at Daily Planet, Clark asks her what is wrong with her mother. Chloe responds that her mother left when she was twelve years old. In the episode Lineage, Chloe and Clark are looking for Rachael Dunleavy and Chloe says her mother left when she was five.
Plot hole: Clark uses his X-Ray vision to see the remains of the girl in the wall, which seems to establish the wall is not made with lead. However, he only reacts to the Kryptonite bracelet inside until he is aware it is there, despite the fact he should have been able to feel its effects long before that.
Continuity mistake: Victor is up in Clark's barn loft using his laptop to read an article about his 'death'. In some scenes the laptop is turned toward Victor, while in one scene, as he says he expected to see angels when he woke up, the laptop is now turned at an angle so that the camera can be seen on the screen.
Continuity mistake: When Victor is going into Lois' apartment with Clark and Lana, he is holding his jacket over his wound to soak up all the "blood". Later, when he goes to see his girlfriend, he is wearing his jacket, but his jacket has only a small stain now.
Continuity mistake: While Chloe and Lex struggle for control of the gun Simone puts both arms down to her side. The shot switches to a slow motion shot of Simone getting shot and instantly Simone has her hand on the jewel again.
Continuity mistake: When Lana goes to see Lance, who's packing up the serum, you see 5 syringes strapped in, 1 with serum in it. When Lance hits Lex and his case falls open, you can see the 5 syringes still strapped in, but now none have any serum in them. When Lance goes to pick up the case, only one syringe is strapped in, and it's in the wrong spot, next to some blood, and one syringe out of the strap lying in the open case.
Other mistake: Maddie and her father can control only glass, but when at the Talon he uses his powers to pull the diamonds out of the stained glass. Diamonds aren't glass.
Suggested correction: This may not necessarily be true by the way their powers work. Remember, diamonds are a form of rock that are clear. Glass is made from melted sand, which is a ground up type of rock that becomes clear. The similarities between diamonds and glass are enough that it is possible they could still do this.
Diamonds are compressed carbon, not a form of rock. Glass is melted silicon. They're both clear materials, that doesn't mean they're equivalent, otherwise they'd be able to control clear plastic or any number of other things too.
If more explanations of their powers were discussed in the show, one might be able to conclude they do or do not have power over diamonds. However, the script only states they have power over glass, they show no propensity for power over sand itself, or other rocks and minerals. As scripted, this remains as error as it go against what is established.
Revealing mistake: At the beginning, Lional's limo comes to a screeching halt on railroad tracks. The camera is panned out to where you can see this happen. The black tire marks that are supposed to appear from the hard braking are already present, which means there were multiple takes.
Character mistake: Chloe is looking at her digital wall of weird for anyone with camouflage abilities in the past and says there's no match. They act like this is a new power. However, in season 1, "Shimmer", Jeff Palmer had the ability to turn invisible because of a cream he made with kryptonite infused green roses. That should have popped up in her search. And even if it didn't, Chloe should remember the ability to turn invisible because she got the cream on her fingers, which turned invisible.
Other mistake: Jonathan Kent's headstone says he was born September 1, 1954. However, in "Relic", we learn Jor-El visited Smallville in 1961, where he met Jonathan's parents and his mom was pregnant with Jonathan. And we know it was him since Hiram (his dad) wanted to name their son Gene and Jessica corrects him and says his name is going to be Jonathan. Plus, if he was born in 1954, he would have been 25 when he won the high school state championship instead of a more realistic 18 if he was born in 1961.
Visible crew/equipment: Episode 22, Season 5 - "Vessel": Lex returns to the mansion, after being abducted, with his new powers. When he shows Lana by shooting his hand, they start talking by the stained glass window. The reflections in their eyes are supposed to be the light coming through the window, but are actually from a white screen used for lighting. The reflections in their eyes are rectangular to confirm this.
Continuity mistake: In Episode 22- Season 5 - "Vessel": At the start, Lex wakes up and heads towards an open field many miles away from the mansion. They show a camera shot of his face in the field and the sky is grey and cloudy, but in the very next shot the sky has turned blue and the sun is shining.
